1. Field of the Invention
The invention relates to an agitator mill for treating free-flowing grinding stock, comprising a grinding receptacle which defines a substantially closed grinding chamber by means of an inner wall; and an agitator which is rotarily drivably disposed therein and which is cup-shaped in relation to a common central longitudinal axis, having an annular cylindrical rotor which has a closed wall; and an interior stator which is disposed within the rotor and fixedly joined to the grinding receptacle; wherein an annular cylindrical exterior grinding chamber is formed between the inner wall of the grinding receptacle and an outer wall of the rotor; and an annular cylindrical interior grinding chamber is formed between an inner wall of the rotor and an outer casing of the interior stator, the interior grinding chamber being arranged coaxially within the exterior grinding chamber and connected thereto via a deflection chamber; wherein the exterior grinding chamber, the deflection chamber and the interior grinding chamber constitute the grinding chamber which is partially filled with auxiliary grinding bodies; wherein a grinding-stock supply area, which is disposed upstream of the exterior grinding chamber and opens into it in the direction of flow of the grinding stock, and a separator device, which is disposed downstream of the interior grinding chamber in the direction of flow, are disposed approximately on the same side of the grinding receptacle for the grinding stock to pass through; wherein auxiliary-grinding-body return conduits are provided in the agitator in an independent auxiliary-grinding-body return module, returning the auxiliary grinding bodies from the vicinity of the separator device into the grinding-stock supply area, the return conduits connecting the end of the interior grinding chamber to the beginning of the exterior grinding chamber; and wherein the inner wall of the grinding receptacle and the outer wall and the inner wall of the rotor are free of interruptions.
2. Background Art
In an agitator mill of the generic type known from DE 41 42 213 A1, the auxiliary-grinding-body return conduits are provided within a stepped annular section which can be formed in one piece together with the rotor bottom, but can also be mounted thereon by screwing. The auxiliary-grinding-body return conduits are straight, having a constant width throughout their length from the inlet to the outlet. Seen from inside outwards, they are set counter to the direction of rotation of the rotor. So as to achieve that the auxiliary grinding bodies are catapulted into the auxiliary-grinding-body return conduits, the separator device is made rotatable. It is further provided with entrainer elements which stand out radially and are intended to catapult, outwards into the auxiliary-grinding-body return conduits, the auxiliary grinding bodies which arrive along with the grinding stock, coming from the interior grinding chamber. This is meant to accomplish that grinding-stock particles that have not been ground do not take a short-cut from the exterior grinding chamber through the auxiliary-grinding-body return conduits towards the separator device. That kind of grinding-stock shooting flows lead to a very rough and thus undesired distribution in particle size of the grinding stock. The described purpose requires considerable constructional implementation in the known agitator mill.